Kamoer sells to many different regions to different distributors. To keep overlapping sales territories Kamoer has put restrictions to help litigate out of region sales. If you purchased the unit in the US the F4 should still work since we distribute to all the Americas and not just the states. If you continue to have issues please submit a support ticket at support.coralvue.com with your issue. They will collect some information and work with Kamoer to get your device activated.